Feature: Added export of Expiration time to Env

[parkeyparker]

In order to calculate time remaining before expiry of a session this will export an extra environment variable: AWSUME_EXPIRATION. With this the remaining time can be calculated and displayed in the prompt in order to determine whether you need to renew the session.

Example usage within .zshrc:

_timeremaining() {
  secs_future=$(date -j -f "%Y-%m-%dT%H:%M:%S" $1 +%s)
  secs_now=$(date +%s)
  secs_remaining=$(( $secs_future - $secs_now ))
  if [ "$secs_remaining" -lt "0" ]; then
  	echo "00:00"
  elif [ "$secs_remaining" -lt "3600" ]; then
  	gdate -d@$secs_remaining -u +%M:%S
  else
    gdate -d@$secs_remaining -u +%H:%M:%S
  fi
}

alias awsenvtimeremain='_awsenvtimeremain'
_awsenvtimeremain() {
  if [[ -v AWSUME_PROFILE ]]; then
    time_remain=$(_timeremaining $AWSUME_EXPIRATION)
    echo "$time_remain"
  fi
}

Then just call awsenvtimeremain() in your prompt definition.

[mbarneyjr]

Hi @parkeyparker,

This looks great! Thanks for the PR! We'll take a look 😄